The goal of this research project is to develop a new approach that combines chromatin immunoprecipitation, tandem affinity purification and mass spectrometry to identify possible activators and/or repressors of the var multigene family encoding the malaria virulence factor, Plasmodium falciparum erythrocyte membrane protein 1, PfEMP1. During their intraerythrocytic development, malaria parasites switch expression to alternative forms of this variant surface protein to evade the host immune response. The genome of each P. falciparum parasite contains approximately 60 var genes distributed on different chromosomes. However, only one var gene is expressed by each parasite in a mutually exclusive manner. The promoter region of var genes plays an important role in this regulation and it is believed that this mechanism might involve specialized repressor (PfVPR) and/or activator (PfVPA) molecules. The specific aims of the current proposal include experimental designs and methods, some newly developed in our laboratories for P. falciparum such as tandem affinity purification and fluorescent in situ hybridization (FISH). They are: Aim I. To identify PfVPA and PfVPR regulators of var gene expression by chromatin immunoprecipitation, tandem affinity purification and mass spectrometry;and Aim II. To initiate a functional analysis of the PfVPA and PfVPR proteins in P. falciparum. PUBLIC HEALTH RELEVANCE: Malaria parasites invade and ultimately destroy circulating red blood cells of their host, often leading to severe clinical illness or death. During their intraerythrocytic development, malaria parasites switch expression to alternative forms of a variant surface protein PfEMP1 encoded by the var genes to evade the host immune response. The goal of this research collaboration is to combine tools and techniques from genetics, molecular biology, and immunochemistry, and the expertise of two laboratories to unravel the molecular determinants of antigenic variation during malaria infection.